The use of time-to-event analysis is common in clinical research. The interpretation of time-to-event analysis can often be misleading. Beginners and early career researchers struggle to grasp the concepts and nuances in a time-to-event analysis. The concepts of censoring, truncation, and bias related to time-to-event analysis are essential for interpreting and applying findings. Regarding bias, lead-time bias and length-time bias are the most important. Lead-time and length-time bias are critical in analysing clinical trials involving time-to-event analysis. This article aims to simplify the concepts of lead-time and length-time bias and some solutions for controlling them.